The focus of this proposed 36 months exploratory qualitative project is to investigate adolescents and young adults who use club drugs in the San Francisco Bay Area. We will focus on the following five research issues: 1) What are the social settings in which club drugs are taken? 2) What are the social, gender and ethnic characteristics of the users of club drugs? 3) What club drugs are currently used, and in what combinations? 4) What are the beliefs, expectations, motivations and perceived attractions for initial and subsequent use of various club drugs, and what are the perceived risks and benefits? 5) What are the psychological, physical and social consequences experienced by those who use club drugs? Using primarily qualitative and ethnographic research methods, we plan to locate and interview 300 young adults who use club drugs, between the ages of 16-25, who have used one or more club drugs three or more times in the previous six months. Half of the proposed sample will be women (150) and half men (150). By utilizing a club drugs screening instrument, a pre-coded descriptive socio-demographic data form, an in-depth semi-structured interview, and a club drugs use matrix, we will examine the complex inter-relationship between club drugs, the users and the social settings. This project is important for two reasons: First, as indicated by our survey of the literature on club drugs, little information is readily available on the use of club drugs by young adults in the U.S., nor on the social world of dance clubs or dance parties, and therefore the use of an exploratory and qualitative approach is appropriate and will remedy an existing and significant research gap by developing detailed information. Second this exploratory project will provide much needed empirical information on the recent increase in the use of club drugs in order to design more effective and appropriate public health initiatives and prevention messages to alert young adults about the dangers of these drugs.